From efc8cc49143c8945e3243380c86571af55e198cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Wed, 19 Jun 2019 10:27:31 +0200
Subject: [PATCH] wip: initial scrolling support (no scrollback though)

---
 grid.c | 24 ++++++++++++++++++++++++
 grid.h |  3 +++
 vt.c   | 14 ++++++++++++--
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/grid.c b/grid.c
index d2287af5..d03765cc 100644
--- a/grid.c
+++ b/grid.c
@@ -3,6 +3,10 @@
 #include <string.h>
 #include <assert.h>
 
+#define LOG_MODULE "grid"
+#define LOG_ENABLE_DBG 1
+#include "log.h"
+
 #define min(x, y) ((x) < (y) ? (x) : (y))
 #define max(x, y) ((x) > (y) ? (x) : (y))
 
@@ -11,6 +15,7 @@ grid_erase(struct grid *grid, int start, int end)
 {
     for (int i = start; i < end; i++) {
         struct cell *cell = &grid->cells[i];
+        /* TODO: memset entire range */
         memset(cell, 0, sizeof(*cell));
 
         cell->attrs.foreground = grid->foreground;
@@ -76,3 +81,22 @@ grid_cursor_down(struct grid *grid, int count)
     int move_amount = min(grid->rows - grid->cursor.row - 1, count);
     grid_cursor_to(grid, grid->cursor.row + move_amount, grid->cursor.col);
 }
+
+void
+grid_scroll(struct grid *grid, int rows)
+{
+    if (rows >= grid->rows) {
+        grid_erase(grid, 0, grid->rows * grid->cols);
+        return;
+    }
+
+    int first_row = rows;
+    int cell_start = first_row * grid->cols;
+    int cell_end = grid->rows * grid->cols;
+    int count = cell_end - cell_start;
+    LOG_DBG("moving %d cells from %d", count, cell_start);
+
+    memmove(&grid->cells[0], &grid->cells[cell_start], count * sizeof(grid->cells[0]));
+    grid_erase(grid, cell_end - rows * grid->cols, grid->rows * grid->cols);
+    grid->all_dirty = true;
+}
diff --git a/grid.h b/grid.h
index 3b806296..5b016830 100644
--- a/grid.h
+++ b/grid.h
@@ -10,7 +10,10 @@ void grid_cursor_right(struct grid *grid, int count);
 void grid_cursor_up(struct grid *grid, int count);
 void grid_cursor_down(struct grid *grid, int count);
 
+void grid_scroll(struct grid *grid, int rows);
+
 int grid_cursor_linear(const struct grid *grid, int row, int col);
 
+
 //void grid_cursor_to(struct grid *grid, int pos);
 //void grid_cursor_move(struct grid *grid, int cols);
diff --git a/vt.c b/vt.c
index 751eece3..1790201a 100644
--- a/vt.c
+++ b/vt.c
@@ -158,7 +158,11 @@ action(struct terminal *term, enum action action, uint8_t c)
         LOG_DBG("execute: 0x%02x", c);
         switch (c) {
         case '\n':
-            grid_cursor_down(&term->grid, 1);
+            LOG_DBG("NEWLINE: %d %d", term->grid.cursor.row, term->grid.rows);
+            if (term->grid.cursor.row == term->grid.rows - 1) {
+                grid_scroll(&term->grid, 1);
+            } else
+                grid_cursor_down(&term->grid, 1);
             break;
 
         case '\r':
@@ -188,8 +192,14 @@ action(struct terminal *term, enum action action, uint8_t c)
         break;
 
     case ACTION_PRINT: {
-        if (term->grid.print_needs_wrap)
+        if (term->grid.print_needs_wrap) {
+            if (term->grid.cursor.row == term->grid.rows - 1) {
+                assert(false);
+                grid_scroll(&term->grid, 1);
+            }
+
             grid_cursor_to(&term->grid, term->grid.cursor.row + 1, 0);
+        }
 
         struct cell *cell = &term->grid.cells[term->grid.linear_cursor];